Trayvon Martin's parents, Tracy Martin and Sybrina Fulton, are still trying to make sense of their family tragedy. They don't feel they have had time yet to really grieve Trayvon's shooting death, which occurred in February. They looked exhausted as they sat down on March 25 outside Orlando for an interview with TIME.

Each hides heartbreak differently: Martin has a more relaxed demeanor, and is quicker to recount happy anecdotes about his son's brief life; Fulton looks more determined, but she is also more shell-shocked, still trying to protect the boy she calls her "baby-faced" teenager. They've been from one press event to another, and they won't be able to eat until after 9:30 p.m. And March 26 is going to be busy: Change.org will present them with a petition signed by more than 2 million people supporting them in their quest to have police arrest the man who shot their son. There is so much more work to do.

The divorced couple say they are left with too many unanswered questions about why their son  who was apparently doing nothing more menacing the evening of Feb. 26 than walking home from a convenience store in Sanford, Fla.  was shot in the chest during an altercation with a neighborhood-watch captain who thought the teen, who was wearing a hoodie, looked "suspicious." To his parents and the cousins he volunteered to babysit, the family friends whose cars he washed, the church-group members he prayed with and the football coaches and teammates he played with, Trayvon, 17, was hardly a delinquent threat. He had his benign, teenage faults  at the time of his death, he was serving a five-day suspension from school for tardiness  but he was, they insist, no felon.

And yet, Martin, 45, and Fulton, 46, say the way the Sanford police department and other local authorities originally handled the case  essentially accepting the word of the watch captain, George Zimmerman, 28, that he shot Trayvon in self-defense, when a good deal of evidence suggests that Zimmerman provoked the incident  implied that their son was the criminal aggressor. "I just need some answers about what happened that night," says Fulton. "Could it have been avoided? What could Zimmerman have done differently? What could Trayvon have done differently? Why was he shot? Why was this a neighborhood-watch captain with a handgun? Why did he remove his handgun from his holster?"

They're convinced that racial bias drove both the shooting and the police indifference and cite factors like the missing-person report that Martin had to file before police even thought to identify Trayvon's body and the fact that investigators never walked him through what they thought happened. "Something was not quite right with the investigation in that regard," Fulton tells TIME. "And it did alarm us." She adds, "I want a detailed account of what happened."

In an observation evoking the memory of Emmett Till  a black 14-year-old from more-racially-tolerant Chicago who was murdered by white bigots while visiting relatives in Mississippi in 1955  Martin and Fulton say Trayvon "never encountered a problem with racism before this incident" while growing up in the cosmopolitan melting pot of Miami. He was in Sanford with family visiting the home of his father's girlfriend.

A detective visited Martin at his girlfriend's house. "He asked me to sit down," Martin recalls. "I sit down. He pulled out a picture of a young gentleman on the ground, dead, and asked me if that was my son. And I confirmed that it was Trayvon. And since that confirmation, it's been a nightmare." Martin called his ex-wife with the news of their son's death. "I didn't actually believe what his dad told me," Fulton says. "I just didn't believe it. That's absolutely the worst call that a mother can receive. That her baby has been shot and killed."

Trayvon was given his name in part to reflect his father Tracy's name. "I wanted his name to be close to mine," says Martin. He remembers his son as a playful child. "Every time he'd hear me come in the house," says Martin, "he'd act like he was asleep. He'd throw his head under the cover and act like he was asleep, and I pulled the cover back, and he'll just bust out laughing." They called him Baby Bear. By the time he was a teenager, his friends were calling him Slim for his 6 ft. 3 in., 140-lb. frame atop his lanky legs.

Trayvon was, they say, a trusting and trustworthy kid, "an athletic, loving, caring person," says Martin, a Miami truck driver. Fulton's face lights up when she describes Trayvon's willingness to do exactly the sort of thing he was doing the night he died: making a snack run for relatives so they could enjoy the NBA All-Star Game on television.

After his parents divorced  an amicable parting  Trayvon served as a liaison between them, "sending little messages back and forth between us," says Martin. Fulton, who works as a government programs manager, says, "Trayvon was a mama's boy. He would give me a kiss in the morning. He would check on us in the evening before I went to bed." When he talked about wanting to attend Florida A&M University in Tallahassee, he blushed when Fulton kiddingly replied, "What, and just leave me at home?"

His sunny nature, his parents say, was reflected by his passion for the outdoors. He was adventurous, and built a ramp for his bicycle "so he could fly in the air." Trayvon, in fact, wanted to be a pilot, and even attended an Experience Aviation training program with Barrington Irving, the youngest and first black pilot to fly solo around the world. Martin says one of his fondest memories of his son was when the boy showed him how to land a plane safely in a flight simulator: "I thought, Wow, my kid can do this."